Many consumers do not want to come into contact with detergent ingredients such as enzymes that are commonly used and found in liquid detergent products, during the washing process. The detergent industry has been trying to prevent or minimise the contact between detergent ingredients such as enzymes and the consumer. For example, the detergent industry minimised the contact between detergent ingredients and the consumer by enclosing, or at least partially enclosing said detergent ingredients with a laminate or film, to produce detergent pouches. Typically said laminate or film comprises water-soluble poly-vinyl alcohol (PVA).
In addition to minimising the contact between detergent ingredients and the consumer, consumers like the benefits of having unit dose detergent products, such as detergent pouches. Many consumers find unit dose detergent products easier and quicker to use during the washing process. For example, by using unit dose detergent products, the amount of detergent to be used during the washing process is already pre-selected for the consumer, negating the need for the consumer to determine, and measure, the desired amount of detergent product which can be a difficult and time consuming procedure.
Unit dose detergent products in the form of pouches are known. For example, EP158464, U.S. Pat. No. 4,846,992, U.S. Pat. No. 4,886,615, U.S. Pat. No. 4,929,380 and U.S. Pat. No. 6,037,319 relate to detergent pouches. Pouches containing liquid detergent compositions are also known. For example EP158464, EP234867, EP656054, U.S. Pat. No. 4,610,799, U.S. Pat. No. 4,846,992, U.S. Pat. No. 4,929,380, U.S. Pat. No. 4,973,410, U.S. Pat. No. 5,395,616, and U.S. Pat. No. 6,037,319 relate to pouches containing a liquid composition.
Films or laminates that are used to enclose, or partially enclose, liquid compositions typically comprise water-soluble PVA. Said films and laminates have the optimum water-dissolution and/or water-disintegration profiles, optimum mechanical strength, and aesthetic properties, that provide pouches which have adequate structural strength during storage and handling by the consumer, adequate aesthetic properties that the consumer likes, and adequate water-dissolution and/or water-disintegration properties when contacted to an aqueous environment such as a wash liquor.
Liquid detergent compositions which comprise enzymes, also typically comprise borate. Said borate acts to stabilise said enzymes in a liquid environment. However, borate and water-soluble PVA interact to form cross-linked PVA, said cross-linked PVA has different structural and chemical properties than water-soluble PVA. Thus, a film or laminate comprising water-soluble PVA, when contacted to borate ions, forms a film or laminate comprising cross-linked PVA, which has poor dissolution properties and poor aesthetic properties, which the consumer does not like, and which does not dissolve and/or disintegrate adequately during the washing process.
Therefore, liquid detergent compositions comprising enzymes, which are enclosed, or at least partially enclosed, by a film or laminate comprising water-soluble PVA to form a pouch, typically comprise low amounts of borate ions, or are free from borate ions, to overcome the problem of the PVA interacting with the borate ions and forming cross-linked PVA. Thus, said liquid detergent compositions have poor enzyme stability properties, which results in poor enzyme activity during the laundering process.